Contact spring group in electromagnetic connecting apparatus



Feb. 19, 1957 E. A. WIBERG 2,782,270

CONTACT SPRING GROUP IN ELECTROMAGNETIC CONNECTING APPARATUS Filed Dec. 1. 1953 2 Sheets-Sheet 1 INVENTOR [R/c 9x52 Mas/w MN- M HTT'OR /VE) E. A. WlBERG Feb. 19, 1957 CONTACT SPRING GROUP IN ELECTROMAGNETIC CONNECTING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 1, 1953 United States Patent CONTACT SPRING GROUP IN ELECTRO- MAGNETIC CONNECTING APPARATUS Eric Axel Wiberg, Stockholm, Sweden, assignor to Telefonaktiebolaget L M Ericsson, Stockholm, Sweden, a corporation of Sweden Application December 1, 1953, Serial No. 395,541

Claims priority, application Sweden December 22, 1952 4 Claims. (Cl. 200-1) The present invention refers to electromagnetic connecting apparatus, especially telephone relays. It relates more exactly to contact spring groups for such apparatus, in which the fore, free ends of the springs are provided with toothed lifting bars for movable contact springs. Said bar is usually mounted between two additional springs, the object of which is to control the bar and determine its right position within the group. The object of the invention is to obtain better room in the group by making at least one of said additional springs superfluous. This is achieved by one of the movable contact springs being provided with a device for locking the lifting bar in said contact spring.

The invention will be described more closely with reference to the accompanying drawings, which show an example of an application of the invention to an electromagnetic relay. Fig. 1 is a perspective view of a contact spring group mounted on a relay. Figs. 2, 3 and 4 illustrate in perspective different phases of the assembly of the lifting bar. Fig. 5 shows the lifting bar. Figs. 6, 7 and 8 show, in a detail of a movable contact spring provided with a locking device, the same phase of the assembly of the bar as in Figs. 2, 3 and 4.

The contact spring group shown in Fig. 1 is mounted on the yoke 3 of a usual electromagnetic telephone relay, the core 1 and the armature 2 of which are indicated on the drawing. The group is constituted by a number of contact springs, which are in a known manner fastened in part of their length and electrically insulated from each other within a pile 4. The free fore ends of the springs, which are provided with contacts, are kept at a determined distance from each other by means of a supporting bar 5 of insulating material provided with teeth and having a predetermined position in relation to the pile 4. There is a toothed lifting bar 11, also of insulating material, for the transmission of the movement of the armature 2 to the movable contact springs 17, 18 of the group. The two upper movable contact springs 17 as well as the lower spring 18 rest against shoulders on the lifting bar, whereas the other contact springs 19 only rest against supports on the rigid supporting bar 5. When the armature 2 is operated the three movable contact springs are moved by the lifting bar towards the three rigid springs, so as to cause contact closing.

In usually used relays, such a supporting bar is mounted between two additional springs. Such an additional spring 13 is shown in Fig. 1 highest in the group. The other additional spring usually lies lowest in the group. According to the present invention said last mentioned spring is replaced by a locking device for the lifting bar 11 on one of the movable contact springs 18. In the present example said locking device consists of a recess 12, Figs. 6, 7 and 8, thus shaped on the fore part of the spring 18, that at assembly the lifting bar 11 is locked by means of'said recess. The lifting bar 11, Fig. 5, is provided with a number of teeth 15, and between said teeth there are grooves 16, one or several of which are narrow, depending on to which one of the springs in the group 2,782,270 Patented Feb. 19, 1957 ice the bar is to be locked. The bar is locked in one of said narrow grooves, the width of which is a little greater than the thickness of the contact springs. How the bar is mounted in the group and locked to the spring 18 will now be explained more clearly with reference to Figs. 2, 3 and 4, which show the front of the contact group, one contact spring group having been omitted.

After assembly of the contact spring group the lifting bar 11 is placed in the back of the holes or recesses in the contact springs 17, 18, 19, as shown in Fig. 2 and the detail of the spring 18 in Fig. 6. The upper part of the bar is thereby made to rest against the contact point of the springs and is somewhat rotated, thereby attaining an intermediate position, shown in Fig. 3 and Fig. 7. After a further push forward the end position shown in Fig. 4 and Fig. 8 is attained. The teeth of the bar thereby come to lie under the movable contact springs 17 and 18, whereas the rigid springs 19 are not fastened to the bar. In the end position the upper part of the bar will mesh into a rectangular hole 14, in the additional upper spring 13. Said hole constitutes the control for the upper part of the bar during the lifting movement caused by the armature 2 and prevents a further rotation of said bar. Since the bar is now prevented from rotating, it cannot leave the recess 12 of the lower movable contact spring. Owing to the shape of said recess the bar can move neither forwards nor backwards. Since, further, the groove 16 in Fig. 5, in which the spring 18 has been introduced, is negligibly wider than the thickness of the spring, the position of the bar is definitely fixed. When the armature operates, the bar 11 moves upwards and carries with itself all the movable contact springs, which have been given a slight initial tension downwards, so as to restore the bar 11 to initial position when the armature releases.

In the shown embodiment the bar has been locked to the lower movable spring 18. It may naturally be locked to some other spring, for example the one which lies right opposite another of the narrow grooves 16 on the bar, Fig. 5. The proposed locking device needs not either necessarily be shaped as the proposed recess 12. It may consist of a recess having some other shape or of some flap on the spring, which is moved into a groove on the bar, or of some other suitable device for determining the position of the bar. In such contact spring groups, in which a movable contact spring lies on top of the group, for example with a normally closed contact against a rigid spring, the additional spring 13 may also be omitted. Said upper contact spring is thereby provided with a recess corresponding to the recess 14 and the lifting bar with. an upper tooth, which after the mounting of the bar in end position forms a shoulder for said movable upper contact spring.

I claim:

17 In a switching device of the class including a plurality of substantially stationary switching blades and a plurality of coacting movable switching blades alternately stacked in spaced relationship electrically insulated from each other, each of said switching blades having a free contact end and an intermediate slot, and an axially movable lifting comb extending through said slots and engaging with its teeth the movable blades for flexing the latter into and out of engagement with the stationary blades upon movement of said comb, one movable switching blade with an intermediate slot having an approximate peripheral outline of two rectangles in longitudinally and laterally staggered relationship, one of said rectangles defining a guide portion and the other a retaining portion, the maximum width of the slot being wider than the thickness of the comb and the maximum length of the slot being longer than the width of the comb, the combined peripheral outline of the slot portions and the peripheral outline of the comb being correlated so as to permit movement of the comb from the guide portion into the retaining portion by lateral dis placement of the comb towards the contact end of the respective blade and by turning of the comb about its longitudinal axis, the intermediate slots of all the other blades having a rectangular peripheral outline providing space for said combined lateral and rotational movement of the comb, the respective teeth of the comb underlying the respective movable blades in the position of the comb nested in said retaining slot portion, and further comprising locking means holding one end of the comb in its nested position in said retaining slot whereby the comb in the said position is secured against lateral displacement toward and away from the contact end of the respective blade and also against axial turning.

2. A switching device according to claim 1 wherein the edge of the rectangles adjacent to the contact end of the respective blade includes a slanted wall portion facilitating axial turning of the comb.

3. A switching device according to claim 1, wherein the comb includes two teeth spaced by an axial distance fitting the thickness of the blade having said slot formed with the guide portion and the retaining portion.

4. A switching device according to claim 1, wherein the said locking means comprise an additional stacked blade having an opening fitting the respective comb end in said nested position of the comb thereby forming said locking means.

References Cited in the file of this patent UNITED STATES PATENTS 2,606,958 Saunders et al. Aug. 12, 1952 2,632,065 Smith et a1 Mar. 17, 1953 2,665,352 Bellamy et al. Ian. 5, 1954 FOREIGN PATENTS 913,4l7 France May 27, 1946 804,220 Germany Apr. 19, 1951 813,060 Germany Sept. 6, 1951 

